Brave’s autofill asks for a complete name, but it’s not very smart when deciding what part of the name is the first name, middle name and last names. It’s based on the anglo-centric notion that everybody’s name is of the type John Smith.
However, things break down quickly with names in most Spanish-speaking countries where it’s very common to have multi-word first names and multi-word last names, with no middle names. Instead of trying to be smart, Brave should ask explicitly for first, middle and last names so it can fill forms correctly. Chrome used to do it like this in the old days, and for some reason they tried to simplify the system making it very hard for us with complex names to be fixing forms every time we’d like to use autofill.